Question

Question. Propose a complete mechanism for the reaction of cyclopentene oxide with sodium methoxide in methanol.

Short answer

Answer.

Step-by-step solution

Attack of methoxide ion as nucleophile on cyclopentene oxide:

Methoxide ion acts as a good nucleophile and attacks at the epoxide ring as epoxide is strained due to presence of angle strain and attack of nucleophile opens up epoxide ring and release strain. Methoxide ion attacks from opposite plane of epoxide as epoxide is formed above the plane, so attack of methoxide ion will be from below the plane.

Attack of methoxide ion as nucleophile

Formation of the product:

After ring opening of epoxide, oxygen acquires negative charge and acts as good base and abstracts proton from methanol which leads to the formation of required product and methoxide ion is formed as side product.

Formation of product